Gingival interleukin-6 concentration following phase I therapy.

There is little information available on the effects of periodontal therapy on tissue levels of interleukin-6 (IL-6). This study compares IL-6 concentrations in gingiva and gingival crevicular fluid (GCF) from patients requiring surgical procedures following Phase I periodontal therapy. Sites requiring surgery due to "unresolved" intrabony pockets were compared to sites not requiring surgery ("resolved") in each patient. Resolved sites had minimal histologic evidence of chronic inflammation and IL-6 accumulation; unresolved sites contained a substantial number of chronic inflammatory cells and IL-6 was widely distributed. IL-6 levels in GCF were significantly greater at resolved than at unresolved gingival sites (P < 0.001); however, IL-6 tissue levels were significantly greater at unresolved than in resolved gingival sites (P < 0.01). These results suggest that IL-6 levels were elevated in gingival connective tissue adjacent to intrabony pockets which had not been resolved following Phase I therapy. Thus, intrabony pocket resolution may be affected by accumulation of IL-6 in the adjacent gingival connective tissue, which may result from increased rates of synthesis or reduced rates of release from gingiva into the GCF.